Top Marks is a great website that provides thousands of learning opportunities through interactive games. A lot of these games can also be used on tablets. The link will take you to the correct Key Stage area where you can search from there for the different subjects and activities.
Oxford Owl is have a range of free home learning resources and activities, including e-Books, which can support Literacy learning at home. They do cover other subject areas but not all are offered free. The link will take you to the Home Learning home page with a list a age ranges for you to select from.